Rec.2020

Rec. 2020 (ITU-R BT.2020) is the color space and parameter set specified for Ultra High Definition Television (4K and 8K) and is the gamut container for most modern HDR formats. Its primaries are dramatically wider than Rec.709, covering approximately 76% of the CIE 1931 chromaticity diagram — including saturated greens, cyans and reds that Rec.709 simply cannot reproduce. The standard supports 10-bit and 12-bit encoding, D65 white point, and is used in conjunction with the PQ (SMPTE ST 2084) or HLG transfer functions for HDR delivery. In practice, current consumer HDR displays do not yet cover the full Rec.2020 gamut: most premium displays reach around 90% of DCI-P3, which is itself only about 70% of Rec.2020. So while masters are encoded in Rec.2020 containers, the actual reachable color volume is closer to P3-D65. This is by design — Rec.2020 acts as a future-proof container that today's displays partially fill and tomorrow's wide-gamut displays will fill more completely. Streaming platforms (Netflix, Disney+, Apple TV+) require HDR masters in Rec.2020 PQ. Grading sessions typically work in P3-D65 limited Rec.2020 (P3 limited inside Rec.2020 encoding) to match what displays can actually show today. Reference: ITU-R BT.2020-2.